EP2643425A1

EP2643425A1 - Compounds for a liquid crystal medium, and the use thereof for high-frequency components

Info

Publication number: EP2643425A1
Application number: EP11782048.0A
Authority: EP
Inventors: Christian Jasper; Atsutaka Manabe; Detlef Pauluth; Volker Reiffenrath
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2010-11-23
Filing date: 2011-10-31
Publication date: 2013-10-02
Anticipated expiration: 2031-10-31
Also published as: TW201226537A; DE102011117048A1; WO2012069133A1; WO2012069133A8; TWI589684B; EP2643425B1

Abstract

The invention relates to compounds with at least one fluorinated C-C double bond between two rings, to the use thereof for high-frequency components, to liquid crystal media containing the compounds, and to high-frequency components containing said media, in particular antennas, especially for the gigahertz range. The liquid crystal media are used for example for phase-shifting microwaves for tunable phased-array antennas.

Description

Compounds for a liquid crystalline medium and their use for high frequency components

The present invention relates to compounds having at least one fluorinated C-C double bond between two rings, their use for high-frequency components, liquid-crystalline media containing the

Connections and high-frequency components containing these media, in particular antennas, especially for the gigahertz range. The

Liquid-crystalline media are used, for example, for phase shifting microwaves for tunable 'phased-array' antennas.

Liquid-crystalline media have long been in electro-optical

Displays (Liquid Crystal Displays - LCDs) used to display information.

1, 4-Diethinylbenzolderivate be in the publications EP 0968988 A1, DE 19907941 A1, DE 10120024 A1 and JP 08012599 A as

liquid crystalline components proposed. Compounds having a (difluoro) ethylene bridge between two rings are not disclosed therein.

Recently, however, liquid-crystalline media are also for use in components, or in components for the

Microwave technology proposed, such. in DE 10 2004 029 429 A and in JP 2005-2088 (A).

A technically valuable application of the liquid-crystalline media in high-frequency technology is based on their property that they can be controlled by a variable voltage in their dielectric properties, especially for the gigahertz range. Thus can be

designing tunable antennas that do not contain any moving parts (A. Gaebler, A. Moessinger, F. Goelden, et al., "Liquid Crystal"). Reconfigurable Antenna Concepts for Space Applications at Microwave and Millimeter Waves, International Journal of Antennas and Propagation, vol. 2009, Article ID 876989, 7 pages, 2009. doi: 10.1 155/2009/876989).

The document A. Penirschke, S. Mueller, P. Scheele, C. Weil, M. Wittek, C. Hock and R. Jakoby: "Cavity Pertubation Method for Characterization of Liquid Crystals up to 35 GHz", 34 ^th European Microwave Conference Amsterdam, 545-548 describes, inter alia, the properties of the known single liquid crystalline substance K15 (Merck KGaA,

Germany) at a frequency of 9 GHz.

1- (phenylethynyl) tolanes, also referred to below as bistolan compounds, with an alkyl substitution on the central phenylene ring are known to the person skilled in the art. For example, discloses the publication S.-T. Wu, C.-S. Hsu, K.-F. Shyu Appl. Phys. Lett. (1999), 74 (3), 344-346 various liquid crystalline bistolane compounds having a lateral methyl group of the formula

C.S. Hsu, K.F. Shyu, Y.Y. Chuang, S.-T. Wu Liq. Cryst. (2000), 27 (2), 283-287 discloses, besides such liquid crystalline bistolane compounds having a lateral methyl group, also corresponding compounds having a lateral ethyl group, and suggests their use, among others. in "liquid crystal optically phased arrays".

DE 10 2004 029 429 A (see above) describes the use of conventional liquid-crystal media in microwave technology, inter alia in phase shifters. There, liquid-crystalline media are already being investigated for their properties in the corresponding frequency range. In the publication DJ. Spells et al. (2002), Liquid Crystals, 29 (12), 1529-32 discloses so-called stilbene-tolan compounds. The

However, compounds carry no lateral substituents and no fluorinated stilbene group. In the document Chin-Yen Chang et al. (2008)

Liquid Crystals, 35 (1), 1-9 are also disclosed stilbene-tolan compounds having an α-methyl stilbene group. The stilbene group is simply methylated, not fluorinated. In the document F. Babudri et al.

(2008), Synthesis, 10, 1580-1588 discloses oligoarylenevinylenes which also include bis-difluorosthenbenes. The compounds are substituted with a number of different polar groups (acids, esters, OH) on the aryl rings and potentially serve as organic semiconductors. Liquid-crystalline properties are not reported therein.

However, the previously known compositions or individual compounds are generally associated with disadvantages. Most of them, among other deficiencies, lead to unfavorably high losses and / or inadequate phase shifts or material quality.

For use in high-frequency technology, liquid-crystalline media with special, hitherto unusual, unusual properties or combinations of properties are needed.

Thus, new components for liquid-crystalline media are with

improved properties required. In particular, the loss in the microwave range must be reduced and the material quality (η) to be improved. For tunable antennas too

Liquid-crystalline media with fast reaction time to a changed voltage between the electrodes of the cell required. There is also a need to improve the low-temperature behavior of the components. Here are both an improvement of

Operating characteristics, as well as the shelf life required.

There is therefore a considerable need for liquid-crystalline media with suitable properties for corresponding practical applications.

Surprisingly, it has been found that the invention

Compounds a much higher clearing point (transition of

nematic phase into the isotropic phase). At the same time, the rotational viscosity (γι) is lower than that of comparative compounds, e.g. those with two acetylene bridges. Taking advantage of this effect, it has now surprisingly been found that liquid crystalline media having a suitable, nematic phase range and high Δη can be realized with the compounds according to the invention, which do not have the disadvantages of the materials of the prior art or at least only to a considerably lesser extent.

The invention relates to compounds of the formula I,

R ¹ - (A ¹ -Z ¹ ) -A ² -A ³ -A ⁴ - (Z ⁵ -A ⁵ ) _n -R ²

wherein

independently of one another a group L or H. L ³ , L ⁴ independently of one another a group L or H, preferably H, independently branched or unbranched alkyl having 1 to 12 C atoms, alkenyl or alkynyl having 2 to 12 C atoms,

in which, independently of one another, one or more hydrogen atoms may be replaced by F or Cl and also one or more non-terminal "-CH ₂ -" - groups may be replaced by O, C ₃ -C ₆ cycloalkyl or C ₃ -C ₆ cycloalkenyl,

F, Cl, Br, CN, NCS, SCN or SF ₅ ,

S or O, preferably S,

A ¹ , A ² , A ⁴ , A ^{5 are} each independently

a) 1,4-phenylene, in which one or more, preferably one or two, CH groups may be replaced by N,

b) a radical from the group thiophene-2,5-diyl or furan-2,5-diyl

or

c) trans-1, 4-cyclohexylene or cyclohexenylene, wherein also one or two non-adjacent CH2 groups may be replaced by -O- and / or -S-, and in which H may be replaced by F, 1, 4-bicyclo (2,2,2) octyl, cylcobut-1, 3-diyl and spiro [3.3] heptane-2,6-diyl, and in which groups a), b) and c)

also one or more H atoms by a group after the

Definition of L may be substituted and wherein preferably at least one group of A ² and A ⁴ , preferably both, represents a group according to definition a) or b), preferably according to a),

where the groups A ² , A ³ and A ^{4 are} preferably substituted by a total of at least one or more groups L,

Y ¹

Z ² -CsC- or - c = C-.

Y ²

Y ¹ , Y ² independently of one another are H, F, Cl, C ₁ -C ₁₀ -alkyl, where at least one group of Y / Y ² denotes F, preferably both F,

Z ¹ , Z ⁵ independently of one another, a single bond, -C = C-, -CH = CH-, -CH ₂ O-, - (CO) O-, -CF ₂ O-, -CF ₂ CF ₂ -, - CH ₂ CF ₂ -, -CH ₂ CH ₂ -, - (CH ₂ ) ₄ -, -CH = CF- or -CF = CF-, where asymmetric bridges can be oriented to both sides,

R ¹ and R ² are each independently a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, wherein in these radicals also one or more CH ₂ - groups each independently of one another by -C = C-, -CH = CH-, -CF = CF-, -CF = CH-, -CH = CF-, - (CO) - and -O- may be replaced so that O atoms are not directly linked to each other,

F, Cl, Br, CN, CF _3, OCF _3, NCS, SCN or SF _5, R ² to H, m, n are independently 0, 1 or 2, and p is 1 or 2 mean.

The double bonds of the formula -CY ¹ = CY ² - between the rings A ² to A ⁴ and optional double bonds in the groups Z ¹ and Z ⁵ preferably have the trans configuration (E configuration).

The compounds of the invention have a high clearing point, a low melting point, an extremely high optical

Anisotropy (Δη). Fast switching times are achieved by a surprisingly low rotational viscosity y. This is an invitation

Adjust phase shifter faster. Another advantage is the relatively low loss factor in the microwave spectrum. The compounds alone or in mixture with other mesogenic components have a nematic phase over a broad temperature range. These properties make them particularly suitable for use in components for high frequency engineering, especially in liquid crystal phase shifters. Liquid-crystalline media according to the invention have the corresponding properties, eg. B. a wide phase range, fast switching time, and also a good low temperature stability.

Preferred compounds of formula I are characterized by the selection of one or more of the following parameters:

The counter m is preferably 0 or 1, more preferably 0. The numerator n is preferably 0 or 1, more preferably 0. m + n is preferably 0 or 1. m + n + p is preferably 1 or 2, i. the total number of ring systems in formula I is preferably 3 or 4.

The groups A ² , A ³ and A ⁴ are particularly preferably substituted by a total of one, two or three groups L. If a group of A ² and A ^{4 is} substituted by L, then this group is preferably independently as A ³ defined in formula I. The ring groups A ¹ and A ⁵ are independently of each other preferably a 1, 4-phenylene, wherein also one or more H atoms can be replaced independently of a group as defined by L independently.

The bridging groups Z ¹ and Z ⁵ are, independently of each other, preferably a single bond, -C = C-, -CF = CF- or -CH = CH-, more preferably a single bond.

Z ² is preferably -C = C- or -CF = CF-, more preferably -C = C-. These groups include a high Δη value and good

Phase properties supported.

Y ¹ / Y ² are preferably H / F, F / H, F / F, Cl / F, CH ² F, F / CH ₃ or F / Cl and more preferably F / F.

One of the radicals R ¹ or R ² , preferably R ¹ , is preferably a straight-chain alkyl radical having 1 to 15 C atoms, wherein in these radicals also one or more Ch ^ groups each independently of one another by -C = C-, -CH = CH-, - (CO) O-, -O (CO) -, - (CO) -, -O- can be replaced so that O atoms are not directly linked to one another. Preferably, the groups R ¹ and R ^{2 are} both an alkyl having 2 to 7 carbon atoms. Here, R ¹ and R ^{2 are,} for example, propyl and hexyl or butyl and butyl, furthermore propyl and pentyl, propyl and hexyl or butyl and pentyl.

In a further preferred embodiment of the invention, the group R ¹ or R ^{2 is} a polar group (radical X). The corresponding compounds of the formula I have a clearly positive dielectric anisotropy (Δε). The Δε value is preferably 3 or more.

Accordingly, preferred compounds of the invention are also

Compounds of the formula IA and IB or preferably IA-1, IA-2, IB-1 and IB-2:

wherein the variable groups are as in formula I and the preferred

Subforms are defined and the groups X, X ¹ and X ² :

X, X ¹ , X ^{2 is} a halogenated alkyl radical having 1 to 7 C atoms, wherein in this radical also one or more CH ₂ - groups each independently of one another by -C = C-, -CH = CH-, -CF = CF -, -CF = CH-, -CH = CF-, - (CO) - and -O- may be replaced by O atoms are not directly linked, F, Cl, Br, CN denote CF _3> OCF ₃ , NCS, SCN or SF ₅ .

Preferably, the groups X ¹ and X ^{2 are} independently F, OCF ₃ , CN, Cl, CF ₃ or NCS. The polar head group of the formulas IA-1, IA-2, IB-1 and IB-2 preferably has the following structure:

Of the group of compounds of the formula IA and IB or IA-1, IA-2, IB-1 and IB-2, the compounds of the formula IA-1 are particularly preferred.

The groups L and L ² or L in the formulas mentioned above and below preferably each independently denote F, Cl, CN, branched or unbranched alkyl, alkenyl or alkynyl having 1 to 8 C atoms, in which one or more independently

Hydrogen atoms may be replaced by F or Cl and also one or more non-terminal "-CH ₂ -" - groups may be replaced by O, substituted or unsubstituted cycloalkyl or cycloalkenyl, particularly preferably F, Cl, alkyl having 1 to 5 C Atoms, alkenyl with 2 to 5

1.2

C atoms, cyclopropyl or cyclobutyl. Preferably, a group of L is F, methyl, ethyl, cyclopropyl or Cl, more preferably F, and the other group is as defined above, or preferably F, Cl, alkyl of 1 to 5 carbon atoms, alkenyl of 2 to 5 C atoms, cyclopropyl, or cyclobutyl.

The groups L ³ and L ⁴ are preferably both H or both are not H, more preferably both H. The ring group A ³ preferably has a substructure selected from the following formulas:

wherein L is defined as L, and more preferably F, methyl or ethyl.

Particularly preferred is a group A ^{3 in} addition to the fluoroethylene bridge, which is so easily substituted that the substituent L points to the side facing away from the fluoroethylene bridge

In the case where p = 2, the two rings A ³ preferably, but not exclusively, together form a biphenyl group selected from the following formulas:

wherein L ^{1 is} defined as L.

Preferred embodiments of the invention are therefore represented by the following exemplary structures: - 12 -

in which the groups are as defined in formula I, in particular R ¹ and R ^{2 are} independently an alkyl radical having 2 to 7 C atoms, for example a propyl and the other group is a hexyl radical or both groups are simultaneously a propyl, butyl, pentyl or hexyl radical. For example, Q is S. L is, for example, F or ethyl.

The compounds of the formula I can advantageously be prepared as shown in the following exemplary synthesis (Scheme 1):

The parameters R ^{1 2} , A ^{1 "5} , Z ^1/5 , m and n are defined therein as above and below, R has the meaning of R ^1/2 . Scheme 1 adequately describes the synthetic approach to the compounds presented here. Depending on the compound, only a different sequence of the experiments described in the example section results.

Scheme 1 shows the synthesis of certain compounds. The phenyl radicals "R-phenyl" can be generalized to any radicals -A ² - (Z ¹ -A ¹ ) _m -R ¹ or -A ⁴ - (Z ⁵ -A ⁵ ) _n -R ² according to formula I. Likewise, the middle ring can be replaced by a radical - [A ³ ] _p - according to formula I. The substituent L may be present one or more times or may be omitted if such a substituent occurs on one of the other rings.

The liquid-crystalline media according to the present invention comprise one or more compounds of the formula I and optionally at least one further, preferably mesogenic compound. The liquid crystal medium therefore preferably contains two or more compounds which preferably liquid crystalline. Preferred media include the preferred compounds of formula I.

Further components of the liquid-crystalline media are preferably selected from the compounds of the formula II:

L ¹¹ R ¹¹ or X ¹¹ ,

L ¹² R ¹² or X ¹² independently of one another unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably having 3 to 10, carbon atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy, or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, carbon atoms, preferably alkyl or unfluorinated alkenyl, independently of one another denote F, Cl, Br, -CN, -NCS, -SCN, -SF ₅ , fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl of 2 to 7 carbon atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, independently 0 or 1, independently trans- CH = CH-, trans- -CF = CF-, -CEC - or mean a single bond, and independently of each other

wherein L independently branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which independently of one another, one or more _"-CH2 -" - groups may be replaced by O, C ₃ -C 6 cycloalkyl, C ₃ -C ₆ cycloalkenyl, fluorinated alkyl or

Alkenyl, fluorinated alkyloxy or alkenyloxy,

F, Cl, Br, CN, NCS, SCN or SF ₅ ,

mean. In a preferred embodiment of the present invention, the liquid-crystalline media comprise one or more compounds of the formula I and one or more compounds of the formula II.

According to the present application, the liquid-crystalline media preferably contain a total of 5 to 95%, preferably 10 to 90% and particularly preferably 15 to 80%, of compounds of the formula I. Preferably, the liquid-crystalline media according to the present invention contain compounds selected from the group of the compounds of formulas I and II, more preferably they are predominantly, even more preferably they are substantially and quite preferably they consist entirely thereof.

In this application means "included" in connection with

Compositions that the entity in question, i. the medium or component, the specified component or components or compound or compounds, preferably in a total concentration of 10% or more, and more preferably 20% or more. "Predominantly" in this context means that the entity in question contains 55% or more, preferably 60% or more and most preferably 70% or more of the indicated component or components or compound or compounds. "Substantially" in this context means that the entity in question contains 80% or more, preferably 90% or more, and most preferably 95% or more of the stated component or components or compound or compounds. "Complete" in this context means that the entity in question contains 98% or more, preferably 99% or more and most preferably 100.0% of the indicated component or components or compound or compounds. According to the present application, the liquid-crystalline media preferably contain a total of 10 to 100%, preferably 20 to 95% and particularly preferably 25 to 90%, of compounds of the formulas I and II.

According to the present invention, the compounds of formula II preferably become stronger in a total concentration of 10% to 90% preferably from 15% to 85%, even more preferably from 25% to 80% and most preferably from 30% to 75% of the total mixture.

The liquid-crystalline media may also contain other additives such as stabilizers, chiral dopants and nanoparticles. The individual compounds added are used in concentrations of 0.005 to 6%, preferably from 0.1 to 3%. The total concentration of these other ingredients is in the range of 0% to 10%, preferably 0.1% to 6%, based on the total mixture. However, the concentration data of the other constituents of the liquid-crystal mixtures, ie the liquid-crystalline or mesogenic compounds, are taken into account without taking into account the concentration of these

Additives indicated. The liquid-crystalline media preferably contain 0 to 10% by weight, in particular 0.01 to 5% by weight and more preferably 0.1 to 3% by weight, of stabilizers. Preferably, the media contain one or more stabilizers selected from 2,6-di-tert-butylphenols, 2,2,6,6-tetramethylpiperidines or 2-benzotriazol-2-yl-phenols. These

Excipients are known in the art and commercially available, for. B. as a sunscreen.

An embodiment of the invention is therefore also a process for the preparation of a liquid-crystal medium, which is characterized in that one or more compounds of the formula I is mixed with one or more further compounds and optionally with one or more additives. The further compounds are preferably selected from the compounds of the formula II, as indicated above, and optionally one or more further compounds.

In the present application, the term dielectrically positive describes compounds or components with Δε> 3.0, dielectrically neutral with -1.5 <Δε <3.0 and dielectrically negative with Δε <-1.5. The dielectric anisotropy of each compound becomes apparent from the results of a solution of 10% of each individual compound in one

determined nematic host mixture. If the solubility of each Compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacities of the test mixtures are determined in a cell with homeotropic as well as homogeneous orientation. The layer thickness is about 20 pm in both cell types. The applied voltage is a square wave with a frequency of 1 kHz and an effective value of typically 0.5V to 1.0V, but is always chosen to be below the capacitive threshold for the particular test mixture. Δε is defined as (ει ι - ε ±), while s is _du cut (ει ι + 2 ε ±) I 3.

As a host mixture for dielectrically positive compounds is the

Mixture ZLI-4792 and for dielectrically neutral as well as for dielectrically negative compounds the mixture ZLI-3086 used, both from Merck KGaA, Germany. The absolute values of the dielectric

Constants of the compounds are determined from the change in the respective values of the host mixture upon addition of the compounds of interest. The values are extrapolated to a concentration of the compounds of interest of 100%.

Components which have a nematic phase at the measuring temperature of 20 ° C are measured as such, all others are treated as compounds. The term threshold voltage refers to in the present

Indicate the optical threshold and are given for 10% relative contrast (V ₀ ), the term saturation voltage refers to optical saturation and is given for 90% relative contrast (V ₉₀ ), in both cases, unless expressly stated otherwise. The capacitive threshold voltage (V ₀ ), also called the Freedericks threshold V _Fr , is only used if expressly stated.

The parameter ranges given in this application all include the limits unless expressly stated otherwise. The different upper and lower limits given for different ranges of properties provide additional preferred ranges in combination. Throughout this application, the following terms and definitions apply unless expressly stated otherwise. All concentrations are given in percentage by weight and refer in each case to the total mixture, all temperatures and all temperature differences are given in degrees Celsius or degree of difference. All physical properties typical of liquid crystals are calculated according to "Merck Liquid

Crystals, Physical Properties of Liquid Crystals ", as of Nov. 1997, Merck KGaA, Germany, and are listed for a temperature of 20 ° C. unless expressly stated otherwise, the optical anisotropy (Δη) is at a wavelength of 589, The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz, the threshold voltages and all other electro-optical

Properties are determined with test cells manufactured at Merck KGaA, Germany. The test cells for the determination of Δε have a layer thickness of about 20 pm. The electrode is a circular ITO electrode with an area of 1.13 cm ² and a guard ring. The alignment layers are SE-121 from Nissan

Chemicals, Japan, for homeotropic alignment (ει ι) and polyimide AL-1054 from Japan Synthetic Rubber, Japan, for homogeneous alignment (ε ±). Capacitance is determined using a Solatron 1260 frequency response analyzer using a sine wave with a voltage of 0.3 ν _^ . The light used in the electro-optical measurements is white light. In this case, a structure with a commercially available device DMS Fa. Autronic Melchers, Germany is used. The characteristic stresses are below vertical

Observation determined. The threshold voltage (Vi ₀ ), mid-gray voltage (V ₅₀ ) and saturation voltage (V ₉₀ ) are determined for 10%, 50% and 90% relative contrast, respectively.

The liquid-crystalline media are investigated for their properties in the frequency range of microwaves as in A. Penirschke et al. "Cavity Perturbation Method for Characterization of Liquid Crystals up to 35GHz ", 34 European Microwave Conference - Amsterdam, pp. 545-548 See also A. Gaebler et al., Direct Simulation of Material Permittivity 12MTC 2009 - International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), p 463-467 and DE 10 2004 029 429 A, in which a measuring method is also described in detail.

The liquid crystal is filled in a capillary made of polytetrafluoroethylene (PTFE) or quartz glass. The capillary has an inner radius of 180 μιη and an outer radius of 350 μιη. The effective length is 2.0 cm. The filled capillary is in the middle of the cavity with a

Resonant frequency of 30 GHz introduced. This cavity has a length of 6.6 mm, a width of 7.1 mm and a height of 3.6 mm.

Then the input signal ("source") is applied and the result of the output signal with a commercial network analyzer

For other frequencies (e.g., 19 GHz), the dimensions of the cavity are adjusted accordingly.

From the change of the resonance frequency and the Q factor, between the measurement with the capillary filled with the liquid crystal and the measurement without the capillary filled with the liquid crystal, the dielectric constant and the loss angle at the corresponding target frequency are calculated by means of equations 10 and 11 of FIG previously mentioned document A. Penirschke et al, 34 ^th European Microwave Conference -. Amsterdam, pp 545-548 determined as described there.

The values for the components of the properties perpendicular to and parallel to the director of the liquid crystal are obtained by orienting the liquid crystal in a magnetic field. For this purpose, the magnetic field of a permanent magnet is used. The strength of the magnetic field is 0.35 Tesla. The orientation of the magnet is adjusted accordingly and then rotated accordingly by 90 °.

The dielectric anisotropy in the μ-wave range is defined as

Δε (ε _Γ, ι ι - ε _{Γι 1} ). The modulability or controllability ("tuneability", τ) is defined as

T = (Δε r / 8 r.l l) ·

The material quality (η) is defined as

η = (τ / tan δ _{∈ r} . _M ax.), with the maximum dielectric loss factor tan 6 _{e rMax} :

tan δ _ε , _Μ3 = max. {tan δ _{ε Γ} . _ι; Tan δ _ε , ιι}

which results from the maximum value of the measured values for tanö _er .

The material quality (η) of the preferred liquid crystal materials is 6 or more, preferably 7 or more, preferably 10 or more, preferably 15 or more, more preferably 25 or more and most preferably 30 or more.

The preferred liquid crystal materials have in the respective components phase shifters of 15 dB or more, preferably 20 dB or more, preferably 307 dB or more, preferably 407 dB or more, preferably 507 dB or more, more preferably 807 dB or more, and most preferably from 1007dB or more.

The liquid-crystal media according to the invention are preferred

nematic phases of at least from -20 ° C to 80 ° C, preferably from -30 ° C to 85 ° C and most preferably from -40 ° C to 100 ° C on. Particularly preferably, the phase is up to 120 ° C or more, preferably up to 140 ° C or more, and most preferably up to 180 ° C or more. In this case, the term "nematic phase" means, on the one hand, that no smectic phase and no crystallization are observed at low temperatures at the corresponding temperature and, on the other hand, that clarification does not yet occur on heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the appropriate temperature and checked by storage in test cells, with a layer thickness of 5 pm, for at least 100 hours. At high temperatures, the clearing point is measured in capillaries by conventional methods. The liquid crystal media according to the present invention preferably have a clearing point of 90 ° C or more, more preferably 100 ° C or more, even more preferably 120 ° C or more, more preferably 150 ° C or more, and most preferably 170 ° C or more, up.

The Δε of the liquid crystal medium according to the invention at 1 kHz and 20 ° C is preferably 1 or more, more preferably 2 or more, and most preferably 3 or more.

The Δη of the liquid crystal media according to the present invention is preferably 589 nm (Na ^D ) and 20 ° C in the range of 0.20 or more to 0.90 or less, more preferably in the range of 0.25 or more to 0.90 or less, more preferably in the range of 0.30 or more to 0.85 or less and most preferably in the range of 0.35 or more to 0.80 or less.

In a preferred embodiment of the present application, the content of the liquid crystal media according to the present invention is preferably 0.50 or more, more preferably 0.55 or more.

Furthermore, the liquid-crystal media according to the invention are characterized by high anisotropies in the microwave range. The birefringence is e.g. at about 8.3 GHz preferably 0.14 or more, more preferably 0.15 or more, more preferably 0.20 or more, more preferably 0.25 or more, and most preferably 0.30 or more. In addition, the birefringence is preferably 0.80 or less.

The liquid crystals used are either individual substances or mixtures. Preferably, they have a nematic phase.

In the present application, unless expressly stated otherwise, the term compounds means both one compound and several compounds. Preferred devices containing a liquid crystal medium or at least one compound according to the invention are phase shifters, varactors, antenna arrays (eg for radio, mobile radio, radio,

Microwaves / radar and other data transmission), matching circuit adaptive filters and others. Preference is given to components for the

High frequency technology as defined above. Preference is also modulated by different applied electrical voltages

Components. Very particularly preferred components are phase shifters. In preferred embodiments, multiple phase shifters are operatively connected, resulting in, for example, a phased array antenna, commonly referred to as a 'phased array' antenna. A group antenna uses the phase shift of the arranged in a matrix transmitting or receiving elements to

Interference to achieve a bundling. From a series or

lattice-like parallel arrangement of phase shifters can be a so-called 'phased array' build, which can be used as a tunable transmission or

Reception antenna for high frequencies (eg Gigahertzbereich) can serve. Inventive 'phased array' antennas have a very wide usable receiving cone.

Preferred applications are radar installations and

Data transmission equipment on manned or unmanned vehicles in the automotive, shipping, aircraft, space and

Satellite technology.

To produce suitable components, in particular phase shifters, a liquid-crystalline medium according to the invention is typically introduced into rectangular cavities of less than 1 mm thickness, several mm wide and several centimeters long. The cavities have opposing electrodes mounted along two long sides. Such arrangements are familiar to the skilled person. By applying a variable voltage when operating the antenna, the

dielectric properties of the liquid-crystalline medium are tuned to set different frequencies or directions of an antenna. The term "halogen" or "halogenated" stands for F, Cl, Br and I, especially for F and Cl and in particular for F. The term "alkyl" preferably comprises straight-chain and branched alkyl groups having 1 to 15 carbon atoms, in particular the

straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. Groups of 2 to 10 carbon atoms are generally preferred.

The term "alkenyl" preferably comprises straight-chain and branched alkenyl groups having 2 to 15 carbon atoms, in particular the straight-chain groups. Particularly preferred alkenyl groups are C ₂ to C ₇ -1 E-alkenyl, C ₄ to C ₇ -3E-alkenyl, C ₅ to C ₇ -4-alkenyl, C ₆ to C ₇ -5-alkenyl and C ₇ -6-alkenyl Alkenyl, in particular C ₂ to C ₇ -1 E-alkenyl, C ₄ to C ₇ - 3E-alkenyl and C ₅ to C ₇ -4-alkenyl. Examples of further preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl , 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups of up to 5 carbon atoms are generally preferred.

The term "alkoxy" preferably comprises straight-chain radicals of the formula C _n H _{2n +} i-O-, where n is 1 to 10. N is preferably 1 to 6. Preferred alkoxy groups are, for example, methoxy, ethoxy, n-

Propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy.

The expression "oxaalkyl" or "alkoxyalkyl" preferably comprises straight-chain radicals of the formula C _n H 2n ₊ i-O- (CH ₂ ) _m , in which n and m are each independently of one another 10. Preferably, n is 1 and m is 1 to 6th

The term "fluorinated alkyl" preferably includes mono- or polyfluorinated radicals. Perfluorinated radicals are included. Particularly preferred are CF ₃ , CH ₂ CF ₃ , CH ₂ CHF ₂ , CHF ₂ , CH ₂ F, CHFCF ₃ and CF ₂ CHFCF ₃ .

The term "fluorinated alkoxy" includes mono- or polyfluorinated radicals. Perfluorinated radicals are preferred. Particularly preferred is the radical OCF ₃ .

The term "substituted cycloalkyl" embraces mono- or polysubstituted alkyl-substituted cycloalkyl, in particular alkyl of 1 to 8

Carbon atoms.

The term "substituted phenyl" includes phenyl which is monosubstituted or polysubstituted by a group such as R ¹ , in particular phenyl which is substituted by F, Cl, alkyl or alkoxy.

In the present application means high frequency technology

Applications with frequencies in the range of 1 MHz to 10 THz, preferably from 1 GHz to 3 THz, more preferably 2 GHz to 1 THz, particularly preferably from 5 to 300 GHz. The application is preferably in the microwave spectrum or adjacent, for the

Message transmission suitable areas in which 'phased array' modules can be used in transmitting and receiving antennas.

The liquid-crystal media according to the invention consist of one or more compounds, preferably from 2 to 30, more preferably from 3 to 20 and most preferably from 3 to 16 compounds. These

Compounds are mixed in a conventional manner. In general, the desired amount of the compound used in the smaller amount is dissolved in the compound used in the larger amount. If the temperature is above the clearing point of the compound used in the higher concentration, the completion of the dissolution process is particularly easy to observe. However, it is also possible, the media in other conventional ways, for example using so-called premixes, which may be, for example, homologous or eutectic mixtures of compounds, or under Use of so-called "multi-bottle" systems, the components of which are themselves ready-to-use mixtures.

All temperatures, e.g. the melting point T (K, N) or T (K, S), the transition from the smectic (S) to the nematic (N) phase T (S, N) and the clearing point T (N, l) of the liquid crystals are in Degrees Celsius indicated. All temperature differences are indicated in degrees of difference.

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to the following

Tables A and B are done. All radicals C _n H _2n + i and C _m H _{2m +} i are

straight-chain alkyl radicals with n or m C atoms; n, m and k are integers and are preferably 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. The coding according to Table B is self-evident. In Table A only the acronym for the main body is given. In individual cases, followed by asterisks, a code for the substituents R, R ^{2 *} , L ^{1 *} and L ^{2 *} follows separately from the acronym for the main body:

Code for R, RR ^{2 *} LL ^{2 *} R ^{2 *} , L ^{1 *} , L ^{2 *} , L ^{3 *}

nO.m OC _n H2n + 1 C _m H2m + 1 HH n C _n H2n + 1 CN HH nN.FC _n H2n + 1 CN FH

nOF OC _n H2n + 1 FHH nF.FC _n H _2n + i FFH nF.FF C _n H2n + 1 FFF

nOCF ₃ .FC _n H _2n +1 OCF _a FH n-Vm C _n H2n + 1 -CH = CH-C _m H2m + i HH Code for R ^r , R ^r R ^{2 *} LL ^{2 *}

R ^{2 *} , L, L ^{2 *} , L ^{3 *}

Suitable mixture components can be found in Tables A and B. TABLE A

EPCH PCH

PTP CCPC

CP BECH

Table B

CBC NMF

PGP nm

CGG-n-F

CPGP-n-m

PPGU-n-F

The following examples illustrate the present invention, oh

restricting it in any way.

From the physical properties, however, it will be clear to the person skilled in the art which properties can be achieved and in which areas they can be modified. In particular, therefore, the combination of the various properties that can preferably be achieved, well defined for the expert.

In the present application, unless expressly stated otherwise, the plural form of a term means both the singular form and the term Plural form, and vice versa. Other combinations of

Embodiments and variants of the invention according to the description will become apparent from the appended claims.

Used abbreviations:

MTB methyl tert-butyl ether

S1O2 silica gel

RT room temperature (about 20 ° C)

Examples

The acetylenes and boronic acids used are commercially available or can be prepared analogously to known syntheses which are known to the person skilled in the art. The radicals "C ₄ Hg" stand for unbranched n-butyl radicals. The same applies to C ₃ H ₇ , C ₆ Hi ₃ , etc. The building block 1, 1, 2-trifluorotriethylsilylethene is synthesized according to: F. Babudri, et al., Eur. J. Org. Chem. 2008, 1977-1982 ,

Synthetic Example 1:

8 g (25.7 mmol) of 1-iodo-2-ethyl-4-bromobenzene and 4.15 g (26.2 mmol) of 4-n-butylphenylacetylene are introduced into 150 ml of NEt.3, with 100 mg

(0.5 mmol) of copper (I) iodide and 360 mg (0.5 mmol) of bis (triphenylphosphine) - palladium (II) chloride, stirred for 3 h at RT and then refluxed for 1 h.

The batch is cooled, treated with water and heptane and the phases are separated. The organic phase becomes more saturated

Natriumchloridlsg. washed, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue will be purified by column chromatography (Si0 ₂ , heptane); the product will get colorless oil.

Synthesis of 1- (4-n-butylphenylethynyl) -2-ethyl-4- (Z-1, 2-difluoro-2-

6.25 g (17.3 mmol) of 1-bromo-3-ethyl-4- (4-n-butyl-phenylethynyl) benzene are initially charged in 100 ml of THF, cooled to -70 ° C. and added dropwise with 12 ml of n -BuLi (1, 6M in hexane, 19.1 mmol). After 1 h, 5 g (24.5 mmol) of 1,1,2-trifluorotriethylsilylethene are added neat and the reaction is warmed to RT overnight before being quenched by the addition of semisaturated ammonium chloride solution. The batch is diluted with MTB and the phases are separated. The aqueous phase is extracted with MTB, the combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue will be

purified by column chromatography (Si0 ₂ , heptane); the product is obtained as a colorless oil.

Synthesis of 1- (4-n-butyl-phenylethynyl) -2-ethyl-4- (E-, 2-difluoroethylene-benzo-benzene

The product obtained from the previous stage (11 mmol) is initially charged in 100 ml of THF and 5 ml of water and treated with 12 ml of a solution of

Tetrabutylammonium fluoride (1 M in THF, 12 mmol) was added. The mixture is stirred for 1.5 h and quenched by the addition of sodium bicarbonate solution and MTB. The phases are separated, the aqueous phase is extracted with MTB, the combined organic phases are washed with saturated sodium chloride solution, over

Dried sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue is purified by column chromatography (S1O2, heptane); the product is obtained as a colorless oil.

Synthesis of 1- (4-n-butylphenylethynyl) -2-ethyl-4- (Z-1, 2-difluoro-2-iodo-ethylenedi-benzene

The product obtained from the previous step (8 mmol) is initially charged in 50 ml of THF, cooled to -70 ° C and treated dropwise with 5.5 ml of n-BuLi (1, 6M in hexane, 8.8 mmol). After 1 h, 2.5 g (9.9 mmol) of iodine in 20 ml of THF are added and the mixture is stirred at -60 ° C. for 2 h. Subsequently, the Heated to 0 ° C and quenched by the addition of water. Then 1 g (4 mmol) of sodium thiosulfate pentahydrate and MTB are added and the phases are separated. The aqueous phase is extracted with MTB, the combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue will be

Synthesis of 1- (4-n-butyl-phenylethynyl) -2-ethyl-4-rE-1,2-difluoro-2- (4-trifluorometh-1-phenylene-ethylene-benzene

3.45 mmol of iodide and 4.21 mmol of boronic acid are introduced into 30 ml of toluene and 0.85 g (8.0 mmol) of Na ₂ C0 ₃ in 15 ml of water and 4 ml of ethanol before 200 mg (0, 17 mmol) of tetrakis- (triphenylphosphine) -palladium (O). The mixture is refluxed for 4 h, cooled and the phases are separated. The aqueous phase is extracted with toluene, the combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue will be

purified by column chromatography (Si0 ₂ , heptane), the other

Purification is carried out by recrystallization from isopropanol. MS (El): m / z (%) = 456 (100, M ⁺ ), 413 (1 1, [M-propylf).

Δε = +2.7

Δη = 0.39

Yi = 877 mPa-s K 43 N 164 I

Analog synthesized:

2) 1- (4-n-butylphenylethynyl) -3-ethyl-4-rE-1,2-difluoro-2- (4-n-butyl-phenvn-ethylenylbenzene

MS (El): m / z (%) = 456 (100, M ⁺ ), 413 (1 1, [M-propylf).

Δε = +0.8

Δη = 0.31

γι = 1578 mPa s

K 45 N 94.4 I

3) 1,4-Bis (E) -1,2-Difluoro-2- (4-n-butyl-phenyl) -ethylenevn-2-ethylbenzene

MS (El): m / z (%) = 494 (100,

Δ∈ = +1, 1

Δη = 0.30

γ _! = 2254 mPa-s

K -2 SmC? (-22) N 1331 4) 1- (4-n-Hexy [-phenylethvnn-2-ethyl-4-rE-1,2-difluoro-2- (4-n-propyl-phenv-O-ethylene-benzene

MS (El): m / z (%) = 470 (100, M ⁺ ), 399 (23, [M-pentylf].

Δε = +2.0

Δη = 0.40

γι = 1377 mPa-s

K 48 N 167 I

5) 1- (4-n-butylphenylethynyl) -2-ethyl-4-rE-1,2-difluoro-2- (3,4,5-trifluorophenvD-ethynylbenzene

MS (El): m / z (%) = 454 (100, M ⁺ ), 439 (5, [M-methylf), 411 (42, [M-propylf], 396 (13, [M-methyl-propylf ).

Δε = +13.8

Δη = 0.35

γι = 518 mPa s

K 94 N 102 I 6) 1- (4-n-Hexylphenylethynyl) -2-ethyl-4-fE-1,2-difluoro-2- (3,4,5-trifluorophenylene-benzene-benzene

MS (El): m / z (%) = 482 (100, M ⁺ ), 467 (3, [M-methylf), 411 (43, [M-pentylf], 396 (12, [M-methyl-pentylf ).

Δε = +12.4

Δη = 0.35

γι = 589 mPa-s

K 72 N 93 I

7) 1- (4-n-Hexyl-phenylethynyl) -2-ethyl-4- [E-1,2-difluoro-2- (3-fluoro-4-trifluoromethoxy-henvD-ethylene-benzene (7)

(7)

MS (El): m / z (%) = 530 (100, M ⁺ ), 459 (36, [M-pentylf).

Δε = +10.2

Δη = 0.34

Υ _! = 780 mPa s

K 62 N 116 I 8) 1- (3-Fluoro-4-trifluoromethoxyphenylethynyl) -2-fluoro-4-rE-1,2-difluoro-2- (4-n-butylphenol-ethyllyllbenzene

MS (El): m / z (%) = 492 (100, M ⁺ ), 449 (70, [M-propylf].

Δε = +15.4

Δη = 0.40

γι = 224 mPa-s

K 77 SmA 220 N 228 I

9) 1- (4-n-pentylphenylethynyl) -2-ethyl-4-rE-1,2-difluoro-2- (3-fluoro-4-trifluoromethoxy-henvD-ethylenylbenzene

MS (El): m / z (%) = 516 (100, M ⁺ ), 459 (37, [M-butylf).

Δε = +10.7

Δη = 0.35

γι = 708 mPa-s

K 64 N 128 I

10) 1- (4-n-pentylphenylethvnn-2-ethyl-4-rE-1,2-difluoro-2- (3,4,5-trifluorophenvd-ethylene-benzene

MS (El): m / z (%) = 468 (100, M ⁺ ), 411 (54, [M-butylf], 396 (14, [M-methyl-butylf).

Δε = +14.2

Δη = 0.36

γι = 559 mPa-s

K 89 N 104 1

11) 1- (3-fluoro-4-trifluoromethoxyphenylethynyl) -2,6-difluoro-4- [E-1, 2-difluoro-4-

MS (El): m / z (%) = 538 (100, M ⁺ ), 467 (75, [M-pentylf).

Δε = +17.9

Δη = 0.34

γ _! = 233 mPa s

K 83 SmA 206 N 209 I 12) 1- (3-Fluoro-4-trifluoromethoxyphenylethynyl) -2-ethyl-4-f E-1,2-difluoro-2- (4-n-hexylphenyl) -ethylenevn-benzene

530 (100, M ⁺ ), 459 (20, [M-pentyl).

13) 1 - (4-n-pentyl-phenoxy) ethane-2-ethyl-4-rE-1,2-difluoro-2- (3-fluoro-4-cyanophenv-ethylvinyl-benzene

MS (El): m / z (%) = 457 (100, M ⁺ ), 400 (46, [M-butyl).

Δε = + 22.3

Δη = 0.48

yi = 3278 mPa s

K 71 N 173 I

14) 1- (4-n-butyl-phenylethynyl) -2-chloro-4-fE-1,2-difluoro-2- (4-n-hexyl-phenvD-ethylenyl-benzene

MS (El): m / z (%) = 490 (100, M ⁺ ), 447 (15, [M-propylf], 419 (17, [M-pentylf), 376 (11, [M-propyl-pentylf ).

K 80 N 203 I

15) 1 - (3-fluoro-4-trifluoromethoxyphenylethvn-2-chloro-4-rE-1,2-difluoro-2-one

MS (El): m / z (%) = 536 (100, M ⁺ ), 465 (66, [M-pentylf).

K 77 SmA 185 N 192 I

16) 1- (4-n-butyl-phenylethynyl) -2-ethyl-4-rE-1,2-difluoro-2- (4-n-propyl-phenyl) -ethylenyl) -benzene

MS (El): m / z (%) = 442 (100, M ⁺ ), 399 (10, [M-propylf]. K 49 N 183 I

17) 1- (3,4,5-trifluorophenylethvnyl) -2,6-difluoro-4-rE-1,2-difluoro-2- (4-n-hexylphenvD-ethylenyllbenzene

MS (El): m / z (%) = 490 (100, M ⁺ ), 419 (82, [M-pentylf).

K 128 SmA 178 N 183 I 18) 1 - (2-Ethyl-4-n-hexyl-phenylethynven-4-f E-1,2-difluoro-2- (4-n-propyl-phenyl) -eth-lenyl] -benzene

MS (El): m / z (%) = 470 (100, M ⁺ ), 399 (25, [M-pentylf). K 34 N 165 I

19) 1- (4-n-butylphenylethynyl) -2-ethyl-4 ^' - er-1, 2-difluoro-2- (4-n-propyl-henyl-ethyl-yl) -biphenyl

MS (El): m / z (%) = 518 (100, M ⁺ ), 475 (8, [M-propyl] ⁺ ), 223 (12, [M-propyl-ethyl] ²⁺ ).

K 103 N 314 I

Mixing Example 1

A liquid crystal medium M-1 having the composition and properties as shown in the following table is prepared. Compound (7) (No. 15) is from Synthesis Example 7.

This mixture is used for microwave applications,

used in particular for phase shifters for 'phased array' antennas.

For comparison, a medium C-1 without the component (7) is prepared from the compounds Nos. 1-14 of the medium M-1, wherein the

Compounds Nos. 1-14 are contained in the same relative amounts. Table: Properties of blends M-1 and C-2 (comparative) at

The controllability τ and the material quality η are opposite to the

Comparison mixture C-1 significantly improved.

Comparative example

1- (4-n-hexylphenylethynyl) -4- (4-n-propylphenylethvnyl) -2-ethylbenzene

Δε = +2

Δη = 0.4

γ, = 1891 mPa-s

K 60 N 122 I

The comparison with Example 4 shows that the compound according to the invention has a broader range of the liquid-crystalline, nematic phase. At the same time, the rotational viscosity γι is lower.

Claims

claims

1.

L ¹ , L ² independently of one another a group L or H,

L ³ , L ⁴ independently of one another are a group L or H, independently branched or unbranched alkyl having 1 to 12 C atoms, alkenyl or alkynyl having 2 to 12 C atoms,

in which, independently of one another, one or more hydrogen atoms may be replaced by F or Cl and also one or more non-terminal "-CH ₂ -" groups may be replaced by O,

C3-C6 cycloalkyl or C3-C6 cycloalkenyl,

F, Cl, Br, CN, NCS, SCN or SF ₅ ,

Qs or O,

A ¹ , A ² , A ⁴ , A ^{5 are} each independently

a) 1,4-phenylene, in which one or more CH groups may be replaced by N, b) a radical from the group thiophene-2,5-diyl or furan-2,5-diyl

or

c) trans-1,4-cyclohexylene or cyclohexenylene, in which also one or two non-adjacent CH ₂ groups may be replaced by -O- and / or -S-, and in which H may be replaced by F, 1, 4- Bicyclo (2,2,2) octylene, cyclopent-1,3-diyl and spiro [3.3] heptane-2,6-diyl, and wherein in groups a), b) and c)

also one or more H atoms by a group after the

Definition of L may be substituted

Y ¹

Z ² -C = C- or - c = C- -

Y

Y ¹ , Y ^{2 are} independently H, F, Cl, C ¹ -C 10 alkyl, where

at least one group of Y ¹ and Y ² F means,

ZZ ⁵ independently of one another a single bond, -C = C-,

-CH = CH-, -CH 2 O-, - (CO) O-, -CF 2 O-, -CF2CF2-, -CH2CF2-, -CH2CH2-, - (CH ₂₎ ₄ -, -CH = CF- or -CF = CF-, where asymmetric bridges can be oriented to both sides,

R ¹ and R ² are each independently a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, wherein in these radicals also one or more CH ₂ - groups each independently of one another by -C = C-, -CH = CH-, -CF = CF-, -CF = CH-, -CH = CF-, - (CO) - and -O- can be replaced so that O atoms are not directly linked to each other,

F, Cl, Br, CN, CF _3, OCF _3, NCS, SCN or SF _5, R ² to H, m, n are independently 0, 1 or 2, and p is 1 or 2

mean.

Compounds according to claim 1, characterized in that Y ¹ and Y ^{2 are of} the formula IF.

Compounds according to claim 1 or 2, characterized in that the GGrupppeennenn AA ²² ,, AA ³³ and A ⁴ is substituted with a total of at least one L group ddaassss

Compounds according to one or more of claims 1 to 3, characterized in that in group A ³

L ^{1 is} a group L.

Compounds according to one or more of claims 1 to 4, characterized in that the rings A ² and A ^{4 is} an optionally substituted 1, 4-phenylene ring.

Compounds according to one or more of claims 1 to 5, characterized in that m + n + p is 1 or 2.

Liquid-crystal medium, characterized in that it contains one or more compounds of the formula I according to one of claims 1 to 6.

8. Liquid crystal medium according to claim 7, characterized in that it additionally contains one or more compounds selected from the compounds of formula II: in which mean:

L ¹¹ R ¹ or X ¹¹ ,

L ¹² R ¹² or X ¹² ,

R ¹¹ and R ^{12 are} independently of each other unfluorinated alkyl or

unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy, or unfluorinated alkoxyalkyl having 2 to 15 C atoms,

X ¹¹ and X ¹² independently of one another are F, Cl, Br, -CN, -NCS, -SCN,

-SF ₅ , fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 carbon atoms, p, q is independently 0 or 1,

Z ¹¹ to Z ^{13 are} independently of one another trans- CH = CH-, trans- -CF = CF-, -C = C- or a single bond, and independently of each other

in which L is independently branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which independently of one another one or more "-CH ₂ -" groups may be replaced by O, C 3 -C 6 -cycloalkyl, C 3 -C 6 -cycloalkenyl, fluorinated alkyl or alkenyl, fluorinated alkyloxy or alkenyloxy,

F, Cl, Br, CN, NCS, SCN or SF ₅ ,

9. A liquid crystal medium according to claim 7 or 8, characterized

characterized in that the concentration of the compounds of

Formula I in the medium ranges from 5% to 95% in total.

10. Use of the compounds of the formula I according to one of

Claims 1 to 6 in a liquid-crystalline medium.

11. Use of the compounds of the formula I according to one of

Claims 1 to 6 in a component for high-frequency technology.

Process for the preparation of a liquid-crystal medium according to one or more of claims 7 to 9, characterized in that one or more compounds of the formula I with one or more several other compounds and optionally mixed with one or more additives.

13. A component for high frequency engineering, characterized in that it comprises a liquid crystal medium according to one or more of

Claims 7 to 9 contains.

14. Component according to claim 13, characterized in that it is one or more functionally connected phase shifter.

15. Use of a liquid-crystal medium after one or

several of claims 7 to 9 in a component for the

High frequency technology.

16. 'Phased array' antenna, characterized in that it contains one or more components according to claim 13 or 14.